CN113474169A

CN113474169A - Adhesive, adhesive for battery packaging material, laminate, battery packaging material, battery container, and battery

Info

Publication number: CN113474169A
Application number: CN202080015567.XA
Authority: CN
Inventors: 小林裕季; 村上伦康; 三原崇; 菅野勉; 中村英美; 神山达哉
Original assignee: DIC Corp
Current assignee: DIC Corp
Priority date: 2019-03-05
Filing date: 2020-02-27
Publication date: 2021-10-01
Also published as: WO2020179610A1; JP7024911B2; JPWO2020179610A1; TW202039762A

Abstract

The invention provides a packaging material for a battery, which has excellent formability, and does not cause a reduction in interlayer adhesion strength or a poor appearance such as interlayer floating after heat-sealing of sealant layers for sealing a battery element and further after a long-term durability test under high temperature and high humidity. A two-component adhesive, a battery packaging material using the same, a battery container and a battery, wherein the two-component adhesive is characterized by comprising a polyol composition (A) and a polyisocyanate composition (B), the polyisocyanate composition (B) comprises an isocyanate compound (B1) and an isocyanate compound (B2), the isocyanate compound (B1) comprises an aromatic polyisocyanate, and the isocyanate compound (B2) comprises at least one selected from the group consisting of diphenylmethane diisocyanate and carbodiimide-modified diphenylmethane diisocyanate.

Description

Adhesive, adhesive for battery packaging material, laminate, battery packaging material, battery container, and battery

Technical Field

The present invention relates to an adhesive, particularly a reactive adhesive suitable for use in a battery packaging material for forming a battery container or a battery package for a lithium ion battery or the like, a laminate obtained using the adhesive, a battery packaging material, a battery container, and a battery.

Background

With the rapid spread of electronic devices such as cellular phones and portable personal computers, there is an increasing demand for various types of batteries such as lithium ion batteries. These batteries are generally made of a metal can (metal can) as a packaging material by sealing electronic elements such as electrodes and electrolytes with a packaging material.

On the other hand, in recent years, with the increase in performance of vehicles such as electric vehicles and hybrid vehicles, household power storage, personal computers, cameras, cellular phones, and the like, batteries are required to have various shapes, and thinning and weight reduction are demanded. However, the battery packaging material of the metal can is difficult to cope with the diversification of the shape, and the weight reduction is limited. Therefore, as a battery packaging material which can be easily processed into various shapes and can be made thin and light in weight, a film-like laminate in which an outer layer side base material layer, an adhesive layer, a metal layer, and a sealant layer are laminated in this order has been proposed.

In order to form a battery container or a battery pack, a battery packaging material including these film-shaped laminates may be molded so that the outer layer side base material layer side is convex and the sealant layer side is concave.

In the battery packaging material, the outer layer side base material layer is an outer layer, and the sealant layer is an inner layer, and the battery elements are sealed by thermally welding the sealant layers around the battery elements to each other when the battery is assembled.

Among them, secondary batteries for vehicle-mounted and household power storage are installed outdoors, and long-term service life is required, and it is required that interlayer adhesiveness between plastic films, metal foils, and the like of a packaging material can be maintained for a long period of time even in an open air environment, and further, that no appearance is abnormal.

In order to improve the properties of these film-like battery packaging materials, various studies have been made focusing on an adhesive layer for bonding a plastic film and a metal layer.

For example, patent document 1 discloses: in a laminated packaging material comprising an inner layer comprising a resin film, a first adhesive layer, a metal layer, a second adhesive layer, and an outer layer comprising a resin film, at least one of the first adhesive layer and the second adhesive layer is formed by an adhesive composition comprising a resin having an active hydrogen group in a side chain, a polyfunctional isocyanate, and a polyfunctional amine compound, whereby a packaging material having high reliability for further molding can be obtained.

Further, patent document 2 discloses: the outer layer side adhesive layer of the battery packaging material having an outer layer side resin film layer, an outer layer side adhesive layer, a metal foil layer, an inner layer side adhesive layer and a heat seal layer is formed by using an adhesive which uses an acrylic polyol (A) having a number average molecular weight of 10000 to 100000 and a hydroxyl value of 1 to 100mgKOH/g and an isocyanate curing agent, and in which the equivalent ratio [ NCO ]/[ OH ] of isocyanate groups derived from an aromatic polyisocyanate (B) contained in the curing agent to hydroxyl groups derived from the acrylic polyol (A) is 10 to 30, whereby the battery packaging material having excellent moldability, not causing a decrease in interlayer adhesion strength even after a long-term durability test, and not causing appearance defects such as interlayer floating can be obtained.

Further, patent document 3 discloses: as the outer layer side adhesive layer having the same configuration as that of patent document 2, a battery packaging material having excellent moldability, not causing a decrease in interlayer adhesion strength and not causing appearance defects such as interlayer floating even after a high temperature and high humidity and long term durability test at 105 ℃ · 100% RH · 168 hours, can be obtained by using an adhesive which uses a polyol component (a) containing a polyester polyol (a1) and an isocyanate curing agent, and in which the equivalent ratio [ NCO ]/([ OH ] + [ COOH ]) of an isocyanate group contained in the curing agent to the total of hydroxyl groups and carboxyl groups derived from the polyol (a): 85 to 99 wt%, and a trifunctional or higher alcohol component (A2): 1 to 15 wt%, wherein the polyester polyol (A1) is a polyester polyol having a number average molecular weight of 5000 to 50000 and comprising a polybasic acid component and a polyhydric alcohol component, and the polybasic acid component comprises 45 to 95 mol% of an aromatic polybasic acid component per 100 mol% of the polybasic acid component.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2008-287971

Patent document 2: japanese patent laid-open No. 2014-185317

Patent document 3: japanese patent laid-open publication No. 2015-82354

Disclosure of Invention

Problems to be solved by the invention

The purpose of the present invention is to provide a battery packaging material having excellent moldability, and which does not cause a decrease in interlayer adhesion strength and a poor appearance such as interlayer floating after heat-sealing of sealant layers for sealing a battery element and further after a long-term durability test under high temperature and high humidity. It is another object of the present invention to provide a reactive adhesive having excellent moldability, heat resistance and moist heat resistance suitable for the production of a battery packaging material.

Means for solving the problems

The present inventors have solved the above-mentioned problems by using a two-component adhesive comprising a polyol composition (a) and a polyisocyanate composition (B), wherein the polyisocyanate composition (B) comprises an isocyanate compound (B1) and an isocyanate compound (B2), the isocyanate compound (B1) comprises an aromatic polyisocyanate, and the isocyanate compound (B2) comprises at least one selected from the group consisting of 2, 2 ' -diphenylmethane diisocyanate, 2, 4 ' -diphenylmethane diisocyanate, 4 ' -diphenylmethane diisocyanate, and carbodiimide-modified diphenylmethane diisocyanate obtained by condensing at least one of these diphenylmethane diisocyanates in the presence of a catalyst.

That is, the present invention relates to a two-component adhesive comprising a polyol composition (a) and a polyisocyanate composition (B), wherein the polyisocyanate composition (B) comprises an isocyanate compound (B1) and an isocyanate compound (B2), the isocyanate compound (B1) comprises an aromatic polyisocyanate, and the isocyanate compound (B2) comprises at least one selected from the group consisting of 2, 2 ' -diphenylmethane diisocyanate, 2, 4 ' -diphenylmethane diisocyanate, and 4, 4 ' -diphenylmethane diisocyanate, and a carbodiimide-modified diphenylmethane diisocyanate obtained by condensing at least one of these diphenylmethane diisocyanates in the presence of a catalyst.

The present invention also relates to a laminate obtained by bonding a plurality of substrates together using the above two-component adhesive.

The present invention also relates to a battery packaging material comprising at least an outer layer-side substrate layer 1, an adhesive layer 2, a metal layer 3, and a sealant layer 4 laminated in this order, wherein the adhesive layer 2 is a cured product of the above-described two-component adhesive.

The present invention also relates to a battery container obtained by molding the battery packaging material described above.

The present invention also relates to a battery using the battery container described above.

ADVANTAGEOUS EFFECTS OF INVENTION

By using the adhesive of the present invention, a battery packaging material having excellent moldability and free from appearance defects such as reduction in interlayer adhesion strength and interlayer floating after heat-sealing of sealant layers for sealing a battery element and further after a long-term durability test under high temperature and high humidity can be obtained. The battery container made of the battery packaging material of the present invention can provide a battery having excellent reliability.

Drawings

Fig. 1 shows an example of a specific embodiment of a laminate in which an outer layer side substrate layer 1, an adhesive layer 2, a metal layer 3, and a sealant layer 4 are laminated in this order according to the present invention.

Fig. 2 shows an example of a specific embodiment of the laminate of the present invention in which an outer layer side substrate layer 1, an adhesive layer 2, a metal layer 3, an adhesive layer 5, and a sealant layer 4 are laminated in this order.

Description of the reference numerals

1: outer side substrate layer

2: adhesive layer

3: metal layer

4: sealant layer

5: adhesive layer

Detailed Description

< adhesive agent >

The adhesive of the present invention is a two-component adhesive comprising a polyol composition (a) and a polyisocyanate composition (B) as essential components, wherein the polyisocyanate composition (B) comprises an isocyanate compound (B1) and an isocyanate compound (B2), the isocyanate compound (B1) comprises an aromatic polyisocyanate, and the isocyanate compound (B2) comprises at least one selected from the group consisting of diphenylmethane diisocyanate and a carbodiimide-modified product of diphenylmethane diisocyanate.

(polyol composition (A))

(polyester polyol (A1))

The polyol composition (a) used for the adhesive of the present invention contains a polyester polyol (a1) containing a polybasic acid or a derivative thereof and a polyhydric alcohol as essential raw materials.

Examples of the polybasic acid or derivative thereof used as a raw material for the polyester polyol (a1) include: aliphatic polybasic acids such as malonic acid, ethylmalonic acid, dimethylmalonic acid, succinic acid, 2-dimethylsuccinic acid, succinic anhydride, alkenylsuccinic anhydride, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid, maleic anhydride, and itaconic acid;

alkyl esters of aliphatic polybasic acids such as dimethyl malonate, diethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, diethyl pimelate, diethyl sebacate, dimethyl fumarate, diethyl fumarate, dimethyl maleate, and diethyl maleate;

alicyclic polybasic acids such as 1, 1-cyclopentanedicarboxylic acid, 1, 2-cyclopentanedicarboxylic acid, 1, 3-cyclopentanedicarboxylic acid, 1, 2-cyclohexanedicarboxylic acid, 1, 3-cyclohexanedicarboxylic acid, 1, 4-cyclohexanedicarboxylic acid, tetrahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, cyclohexane-1, 2, 4-tricarboxylic acid-1, 2-anhydride, nadic anhydride, and chlorendic anhydride;

aromatic polybasic acids such as phthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride, 1, 4-naphthalenedicarboxylic acid, 2, 5-naphthalenedicarboxylic acid, 2, 6-naphthalenedicarboxylic acid, 2, 3-naphthalenedicarboxylic anhydride, naphthalenedicarboxylic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, biphenyldicarboxylic acid, 1, 2-bis (phenoxy) ethane-p, p' -dicarboxylic acid, benzophenone tetracarboxylic dianhydride, 5-sodium sulfonate isophthalate, tetrachlorophthalic anhydride, and tetrabromophthalic anhydride;

methyl esters of aromatic polybasic acids such as dimethyl terephthalate and dimethyl 2, 6-naphthalenedicarboxylate; etc., 1 or 2 or more species may be used in combination.

The polyol may be a diol or a trifunctional or higher polyol, and the diol includes: aliphatic diols such as ethylene glycol, diethylene glycol, propylene glycol, 1, 3-propanediol, 1, 2, 2-trimethyl-1, 3-propanediol, 2, 2-dimethyl-3-isopropyl-1, 3-propanediol, 1, 4-butanediol, 1, 3-butanediol, 3-methyl-1, 3-butanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, neopentyl glycol, 1, 6-hexanediol, 1, 4-bis (hydroxymethyl) cyclohexane, and 2, 2, 4-trimethyl-1, 3-pentanediol;

ether glycols such as polyoxyethylene glycol and polyoxypropylene glycol;

modified polyether glycols obtained by ring-opening polymerization of the above aliphatic glycols and various cyclic ether bond-containing compounds such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether and allyl glycidyl ether;

lactone polyester polyols obtained by polycondensation of the above aliphatic diols with various lactones such as a lactone and epsilon-caprolactone;

bisphenols such as bisphenol a and bisphenol F;

and alkylene oxide adducts of bisphenols obtained by adding ethylene oxide, propylene oxide, and the like to bisphenols such as bisphenol a and bisphenol F.

Examples of the trifunctional or higher polyhydric alcohol include: aliphatic polyhydric alcohols such as trimethylolethane, trimethylolpropane, glycerin, hexanetriol, and pentaerythritol;

modified polyether polyols obtained by ring-opening polymerization of the above aliphatic polyhydric alcohols and various cyclic ether bond-containing compounds such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether and allyl glycidyl ether;

lactone polyester polyols obtained by polycondensation of the above aliphatic polyols with various lactones such as epsilon-caprolactone.

In the present invention, the polyol preferably contains a branched alkylene glycol in order to improve the appearance of the laminate.

Specifically, the branched alkylene glycol is an alkylene glycol having a tertiary carbon atom or a quaternary carbon atom in its molecular structure, and examples thereof include 1, 2, 2-trimethyl-1, 3-propanediol, 2, 2-dimethyl-3-isopropyl-1, 3-propanediol, 3-methyl-1, 3-butanediol, 3-methyl-1, 5-pentanediol, neopentyl glycol, 1, 4-bis (hydroxymethyl) cyclohexane, and 2, 2, 4-trimethyl-1, 3-pentanediol, and these may be used alone or in combination of two or more. Among these, neopentyl glycol is preferable from the viewpoint of obtaining a polyester polyol (a1) having excellent wet heat resistance.

In the present invention, the polyester polyol (a1) may be a polyester polyurethane polyol which is essentially composed of a polybasic acid or a derivative thereof, a polyhydric alcohol and a polyisocyanate. Examples of the polyisocyanate used in this case include a diisocyanate compound and a trifunctional or higher polyisocyanate compound. These polyisocyanates may be used alone or in combination of two or more.

Examples of the diisocyanate compound include: aliphatic diisocyanates such as butane-1, 4-diisocyanate, hexamethylene diisocyanate, 2, 4-trimethylhexamethylene diisocyanate, 2, 4, 4-trimethylhexamethylene diisocyanate, xylylene diisocyanate, m-tetramethylxylylene diisocyanate, and lysine diisocyanate;

alicyclic diisocyanates such as cyclohexane-1, 4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4, 4 '-diisocyanate, 1, 3-bis (isocyanatomethyl) cyclohexane, methylcyclohexane diisocyanate, isopropylidene dicyclohexyl-4, 4' -diisocyanate, norbornane diisocyanate and the like;

aromatic diisocyanates such as 1, 5-naphthalene diisocyanate, 4 ' -diphenylmethane diisocyanate, 4 ' -diphenyldimethylmethane diisocyanate, 4 ' -dibenzyl diisocyanate, dialkyl diphenylmethane diisocyanate, tetraalkyl diphenylmethane diisocyanate, 1, 3-phenylene diisocyanate, 1, 4-phenylene diisocyanate, and toluene diisocyanate.

Examples of the trifunctional or higher polyisocyanate compound include an adduct type polyisocyanate compound having a urethane bond site in the molecule and a urethane type polyisocyanate compound having an isocyanurate ring structure in the molecule.

The adduct-type polyisocyanate compound having a urethane bond site in the molecule is obtained by, for example, reacting a diisocyanate compound with a polyol. Examples of the diisocyanate compound used in this reaction include various diisocyanate compounds exemplified as the above-mentioned diisocyanate compounds, and these may be used alone or in combination of two or more. The polyol compound used in the reaction may be exemplified by various polyol compounds exemplified as the above-mentioned polyol, a polyester polyol obtained by reacting a polyol with a polybasic acid, and the like, and these may be used alone or in combination of two or more.

The urethane polyisocyanate compound having an isocyanurate ring structure in the molecule is obtained by, for example, reacting a diisocyanate compound with a monool and/or a diol. Examples of the diisocyanate compound used in this reaction include various diisocyanate compounds exemplified as the above-mentioned diisocyanate compounds, and these may be used alone or in combination of two or more. Examples of the monool used in this reaction include hexanol, 2-ethylhexanol, octanol, n-decanol, n-undecanol, n-dodecanol, n-tridecanol, n-tetradecanol, n-pentadecanol, n-heptadecanol, n-octadecanol, n-nonadecanol, eicosanol, 5-ethyl-2-nonanol, trimethylnonanol, 2-hexyldecanol, 3, 9-diethyl-6-tridecanol, 2-isoheptylisoundecanol, 2-octyldodecanol, and 2-decyltetradecanol, and examples of the diol include the aliphatic diols exemplified in the above-mentioned polyhydric alcohols. These monools and diols may be used alone or in combination of two or more.

The polyester polyol (a1) used in the present invention is a reaction product of a polybasic acid or a derivative thereof and a polyhydric alcohol, and the proportion of the polybasic acid having an aromatic ring or a derivative thereof in the polybasic acid or the derivative thereof is preferably 30 mol% or more. This makes it possible to obtain an adhesive having excellent storage stability. Further, from the viewpoint of improving moldability and heat resistance, the proportion of the polybasic acid having an aromatic ring or the derivative thereof in the polybasic acid or the derivative thereof is more preferably 50 mol% or more, more preferably 70 mol% or more, and still more preferably 96 mol% or more. The polybasic acids or derivatives thereof may each be a polybasic acid having an aromatic ring.

Alternatively, the polyester polyol (a1) used in the present invention may be a reaction product of a polybasic acid or a derivative thereof with a polyhydric alcohol and a polyisocyanate, and the proportion of the polybasic acid having an aromatic ring or a derivative thereof in the polybasic acid or a derivative thereof is preferably 30 mol% or more. This makes it possible to obtain an adhesive having excellent storage stability. Further, from the viewpoint of improving moldability and heat resistance, the proportion of the polybasic acid having an aromatic ring or the derivative thereof in the polybasic acid or the derivative thereof is more preferably 50 mol% or more, more preferably 70 mol% or more, and still more preferably 96 mol% or more. The polybasic acids or derivatives thereof may each be a polybasic acid having an aromatic ring.

The hydroxyl value of the polyester polyol (A1) used in the present invention is preferably in the range of 1 to 40mgKOH/g, more preferably 3mgKOH/g or more, and 30mgKOH/g or less, from the viewpoint of further excellent adhesive strength.

The number average molecular weight (Mn) of the polyester polyol (a1) used in the present invention is preferably in the range of 2000 to 100000, more preferably 2000 to 50000, from the viewpoint of further improving the adhesive strength when used for adhesive applications. When the number average molecular weight is less than 2000, the crosslinking density in the cured coating film may become too high, resulting in poor appearance and moldability of the laminate.

On the other hand, the weight average molecular weight (Mw) is preferably in the range of 5000 to 300000, more preferably in the range of 10000 to 200000.

In the present invention, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are values measured by Gel Permeation Chromatography (GPC) under the following conditions.

A measuring device: HLC-8320GPC, manufactured by Tosoh corporation

Column: TSKgel 4000HXL, TSKgel 3000HXL, TSKgel2000HXL, TSKgel 1000HXL manufactured by Tosoh Co

A detector: RI (differential refractometer)

Data processing: Multi-STATION GPC-8020model II manufactured by Tosoh corporation

The measurement conditions were as follows: column temperature 40 deg.C

Solvent tetrahydrofuran

Flow rate 0.35 ml/min

The standard is as follows: monodisperse polystyrene

Sample preparation: a tetrahydrofuran solution was filtered through a microfilter at 0.2 mass% in terms of solid content of the resin to obtain a sample (100. mu.l)

The solid acid value of the polyester polyol (A1) used in the present invention is not particularly limited, but is preferably 10.0mgKOH/g or less. A content of 5.0mgKOH/g or less is preferable because the moist heat resistance is further excellent. The lower limit of the acid value of the solid content is not particularly limited, but is, for example, 0.5mgKOH/g or more. It may be 0 mgKOH/g.

The glass transition temperature of the polyester polyol (a1) used in the present invention is not particularly limited, and is preferably-30 ℃ or higher, more preferably-20 ℃ or higher, in order to suppress the overflow of the adhesive during dry lamination in the production of a laminate. The upper limit is not particularly limited, but is preferably 110 ℃ or lower in view of storage stability and productivity.

The polyester polyol (a1) used in the present invention may contain two or more polyester polyols having different glass transition temperatures. In this case, it is preferable to include a polyester polyol having a glass transition temperature of-30 ℃ or higher and 20 ℃ or lower and a polyester polyol having a glass transition temperature of 50 ℃ or higher and 110 ℃ or lower. This improves heat resistance and moist heat resistance.

The glass transition temperature in the present invention refers to a value measured in the following manner.

Using a differential scanning calorimeter (SII NAOTECNOLOGY, DSC-7000, hereinafter referred to as DSC), 5mg of a sample was heated from room temperature to 200 ℃ at 10 ℃ per minute under a 30 mL/minute nitrogen gas flow, and then cooled to-80 ℃ at 10 ℃ per minute. The temperature was again raised to 150 ℃ at 10 ℃/min, the DSC curve was measured, and the intersection of the straight line extending from the baseline on the low temperature side to the high temperature side in the measurement results observed in the second temperature raising step and the tangent drawn at the point where the slope of the curve in the step-like portion of glass transition became maximum was regarded as the glass transition point, and the temperature at that time was regarded as the glass transition temperature. The temperature is increased to 200 ℃ by the first temperature increase, and it may be adjusted as appropriate if the temperature is such that the polyester polyol (a1) is sufficiently melted, but is insufficient at 200 ℃. Similarly, when the cooling temperature is not sufficient at-80 ℃ (for example, when the glass transition temperature is lower), the temperature is appropriately adjusted.

In the synthesis of the polyester polyol (a1), the reaction of the polybasic acid or the derivative thereof with the polyhydric alcohol, or the reaction of the polybasic acid or the derivative thereof with the polyhydric alcohol and the polyisocyanate may be carried out according to a known method.

For example, the reaction of the polybasic acid or derivative thereof with the above-mentioned polyol may be carried out by polycondensation. In the reaction between the polyol and the polyisocyanate, the polyester polyol obtained by reacting the polyol with the polybasic acid or the derivative thereof according to the above-mentioned method is reacted with the polyisocyanate in the presence of a known and conventional urethanization catalyst as required, whereby the polyester polyol (a1) of the present invention can be obtained.

In the esterification reaction of a polybasic acid or a derivative thereof with a polyhydric alcohol, the polybasic acid or the derivative thereof, the polyhydric alcohol, and a polymerization catalyst are charged into a reaction vessel equipped with a stirrer and a rectification device, and the temperature is raised to about 130 ℃ under normal pressure while stirring. Thereafter, the resulting water is distilled off at a reaction temperature in the range of 130 to 260 ℃ while raising the temperature at a rate of 5 to 10 ℃ for 1 hour. After the esterification reaction for 4 to 12 hours, the reaction is accelerated by distilling off the excessive polyol while gradually raising the reduced pressure from the normal pressure to a range of 1 to 300torr, whereby a polyester polyol (A1) can be produced.

The polymerization catalyst used in the esterification reaction is preferably a polymerization catalyst containing at least 1 metal selected from

groups

2, 4, 12, 13, 14 and 15 of the periodic table of the elements or a metal compound thereof. Examples of the polymerization catalyst containing the metal or the metal compound thereof include metals such as Ti, Sn, Zn, a1, Zr, Mg, Hf, and Ge; compounds of these metals, more specifically, titanium tetraisopropoxide, titanium tetrabutoxide, titanium acetylacetonate, tin octylate, 2-ethylhexyltin, zinc acetylacetonate, zirconium tetrachloride tetrahydrofuran complex, hafnium tetrachloride tetrahydrofuran complex, germanium oxide, germanium tetraethoxide, and the like.

As commercially available polymerization catalysts usable in the esterification reaction, organic tin catalysts, inorganic metal catalysts, and inorganic tin compounds manufactured by Songhua Fine Chemicals, ORGATIX TA series, TC series, ZA series, ZC series, AL series, and Nissan chemical corporation are preferably listed.

The amount of the polymerization catalyst is not particularly limited as long as the esterification reaction can be controlled and a good-quality polyester polyol (A1) can be obtained, and is, for example, 10 to 1000ppm, preferably 20 to 800ppm based on the total amount of the polybasic acid or the derivative thereof and the polyhydric alcohol. Further, in order to suppress coloring of the polyester polyol (A1), it is more preferably 30 to 500 ppm.

Further, the polyester-polyurethane polyol used in the present invention is obtained by chain-extending the polyester polyol obtained by the above-described method with a polyisocyanate. Specifically, a polyester polyol, a polyisocyanate, a chain extension catalyst, and a good solvent for the polyester polyol and the polyisocyanate, which is used as needed, are charged into a reaction vessel and stirred at a reaction temperature of 60 to 90 ℃. The reaction is carried out until substantially no isocyanate groups from the polyisocyanate used remain, to obtain the polyester-polyurethane polyol used in the present invention.

As the chain extension catalyst, a known and commonly used catalyst used as a general urethane-forming catalyst can be used. Specific examples thereof include organic tin compounds, organic tin carboxylates, lead carboxylates, bismuth carboxylates, titanium compounds, zirconium compounds, and the like, and they may be used alone or in combination. The amount of the chain extension catalyst to be used may be an amount sufficient to promote the reaction between the polyester polyol and the polyisocyanate, and specifically, is preferably 5.0% by mass or less based on the total amount of the polyester polyol and the polyisocyanate. In order to suppress hydrolysis and coloring in the resin due to the catalyst, the content is more preferably 1.0% by mass or less. Further, these chain extension catalysts can be used in consideration of the action of curing catalysts of the polyol composition (a) and the isocyanate composition (B) described later.

Examples of the method for confirming the remaining isocyanate group include: 2260cm, which is an absorption spectrum derived from isocyanate groups, was confirmed by infrared absorption spectroscopy^-1An absorption peak observed in the vicinity of the isocyanate group, and the quantitative determination of the isocyanate group by titration.

Examples of the good solvent for producing the polyester-polyurethane polyol include ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, toluene, xylene, and the like. These may be used alone or in combination of two or more.

(polyisocyanate composition (B))

The polyisocyanate composition (B) used in the present invention comprises an isocyanate compound (B1) and an isocyanate compound (B2). The isocyanate compound (B1) contains an aromatic polyisocyanate, and the isocyanate compound (B2) contains at least one selected from the group consisting of diphenylmethane diisocyanate and a carbodiimide-modified product of diphenylmethane diisocyanate. In the present invention, the aromatic polyisocyanate (B1) does not contain diphenylmethane diisocyanate (B2). The polyisocyanate composition (B) may contain other isocyanate compounds as required.

The isocyanate compound (B1) is a compound in which an isocyanate group is directly bonded to an aromatic ring, and specific examples thereof include aromatic diisocyanates such as 1, 5-naphthalene diisocyanate, 4 ' -diphenyldimethylmethane diisocyanate, 4 ' -dibenzyl diisocyanate, dialkyl diphenylmethane diisocyanate, tetraalkyl diphenylmethane diisocyanate, 1, 3-phenylene diisocyanate, 1, 4-phenylene diisocyanate, and toluene diisocyanate, oligomers of these diisocyanates, 2 ' -diphenylmethane diisocyanate, 2, 4 ' -diphenylmethane diisocyanate, 4 ' -diphenyldimethylmethane diisocyanate, adduct type polyisocyanate compounds, and mixtures thereof, A urethane type polyisocyanate compound, and the like. This makes it possible to obtain an adhesive having excellent heat resistance and moist heat resistance.

The isocyanate compound (B1) may have 2 isocyanate groups in one molecule, and more preferably has 3 or more isocyanate groups in 1 molecule. Among them, tolylene diisocyanate and derivatives of tolylene diisocyanate (oligomers of tolylene diisocyanate, adduct type polyisocyanate compounds, and urethane type polyisocyanate compounds) are preferably used, adduct type polyisocyanate compounds of tolylene diisocyanate are more preferably used, and adduct of tolylene diisocyanate and trimethylolpropane are further preferably used. The toluene diisocyanate may be either 2, 4-toluene diisocyanate or 2, 6-toluene diisocyanate alone or a mixture thereof.

The isocyanate compound (B2) may be 2, 2 ' -diphenylmethane diisocyanate, 2, 4 ' -diphenylmethane diisocyanate, 4 ' -diphenylmethane diisocyanate alone, or a carbodiimide-modified diphenylmethane diisocyanate obtained by condensing at least one of these diphenylmethane diisocyanates in the presence of a catalyst, or may be any 2 or more in combination. From the viewpoint of excellent workability, 4' -diphenylmethane diisocyanate is preferably contained.

The other isocyanate compound (B3) is not particularly limited as long as it has 2 or more isocyanate groups in one molecule, and various compounds can be used. Specifically, the various diisocyanate compounds exemplified as the raw materials of the polyester polyol (a1), adduct-modified diisocyanate compounds obtained by reacting various diisocyanate compounds with a diol compound, biuret modified products, allophanate modified products thereof, and various trifunctional or higher polyisocyanate compounds can be used either singly or in combination of two or more.

(other Components of the adhesive)

The adhesive of the present invention may be used in combination with other components within a range not impairing the effects of the present invention. For example, in the polyol composition (a), it is preferable to contain a polycarbonate polyol compound in addition to the polyester polyol (a 1). In this case, the blending ratio of the total amount of the polyester polyol (a1) and the polycarbonate polyol compound is preferably in the range of 30 to 99.5 mass%, and preferably in the range of 60 to 99 mass% with respect to the total mass of the polyester polyol (a1) from the viewpoint of providing an adhesive agent having high adhesion to various substrates and excellent moist heat resistance.

The number average molecular weight (Mn) of the polycarbonate polyol compound is preferably in the range of 300to 2000 from the viewpoint of being an adhesive agent having high adhesion to various substrates and excellent moist heat resistance. The hydroxyl value is preferably in the range of 30 to 250mgKOH/g, more preferably in the range of 40 to 200 mgKOH/g. Further, the polycarbonate polyol compound is preferably a polycarbonate diol compound.

In addition, the polyol composition (a) preferably contains a polyoxyalkylene-modified polyol compound in addition to the polyester polyol (a 1). In this case, the blending ratio of the total amount of the polyester polyol (a1) and the polyoxyalkylene modified polyol compound is preferably in the range of 30 to 99.5 mass%, and preferably in the range of 60 to 99 mass%, with respect to the total mass of the polyester polyol (a1), from the viewpoint of providing an adhesive agent having high adhesion to various substrates and excellent moist heat resistance.

The number average molecular weight (Mn) of the polyoxyalkylene modified polyol compound is preferably in the range of 300to 2000 from the viewpoint of being an adhesive agent having high adhesion to various substrates and excellent moist heat resistance. The hydroxyl value is preferably in the range of 40 to 250mgKOH/g, more preferably in the range of 50 to 200 mgKOH/g. Further, the polyoxyalkylene modified polyol compound is preferably a polyoxyalkylene modified glycol compound.

The polyol composition (a) used in the present invention may contain other resin components in addition to the polyester polyol (a 1). When other resin components are used, they are used preferably at 50 mass% or less, and preferably at 30 mass% or less, based on the total mass of the main component. Specific examples of the other resin component include epoxy resins. Examples of the epoxy resin include bisphenol type epoxy resins such as bisphenol a type epoxy resin and bisphenol F type epoxy resin; biphenyl type epoxy resins such as biphenyl type epoxy resin and tetramethylbiphenyl type epoxy resin; dicyclopentadiene-phenol addition reaction type epoxy resins, and the like. They may be used alone or in combination of two or more. Among these, bisphenol type epoxy resins are preferably used because they have high adhesion to various substrates and excellent moist heat resistance.

The number average molecular weight (Mn) of the epoxy resin is preferably in the range of 300to 2000, from the viewpoint of being an adhesive agent having high adhesiveness to various substrates and excellent moist heat resistance. Further, the epoxy equivalent is preferably in the range of 150 to 1000 g/equivalent.

In the case of using the above epoxy resin, the blending ratio of the total amount of the polyester polyol (a1) and the epoxy resin is preferably in the range of 30 to 99.5 mass%, and preferably in the range of 60 to 99 mass% with respect to the total mass of the polyester polyol (a1) from the viewpoint of providing an adhesive agent having high adhesion to various substrates and excellent moist heat resistance.

The above polyol composition (a) used in the present invention may contain an adhesion-imparting agent. Examples of the tackifier include rosin-based or rosin ester-based tackifiers, terpene-based or terpene-phenol-based tackifiers, saturated hydrocarbon resins, coumarone-based tackifiers, coumarone indene-based tackifiers, styrene resin-based tackifiers, xylene resin-based tackifiers, phenol resin-based tackifiers, petroleum resin-based tackifiers, and ketone resin-based tackifiers. The ketone resin-based tackifier, the rosin-based tackifier or the rosin ester-based tackifier are preferable, and the ketone resin-based tackifier is more preferable. They may be used alone or in combination of two or more. When the tackifier is used, the total mass of the polyester polyol (a1) is preferably 80 to 99.99 mass%, more preferably 85 to 99.9 mass%, based on the total mass of the polyester polyol (a1) and the tackifier.

Examples of the rosin-based or rosin ester-based resins include polymerized rosin, disproportionated rosin, hydrogenated rosin, maleated rosin, fumarated rosin, and glycerol esters thereof, pentaerythritol ester, methyl ester, ethyl ester, butyl ester, ethylene glycol ester, diethylene glycol ester, and triethylene glycol ester.

Examples of the terpene-based or terpene-phenolic type include an oligomeric terpene-based, an α -pinene polymer, a β -pinene polymer, a terpene-phenolic type, an aromatic modified terpene-based, and a hydrogenated terpene-based.

Examples of the petroleum resin system include petroleum resins obtained by polymerizing petroleum fractions having 5 carbon atoms, which are obtained from pentene, pentadiene, isoprene, and the like; petroleum resins obtained by polymerizing petroleum fractions having 9 carbon atoms, which are obtained from indene, methylindene, vinyltoluene, styrene, α -methylstyrene, β -methylstyrene, or the like; copolymerized petroleum resins of C5 to C9 obtained from the above-mentioned various monomers and petroleum resins obtained by hydrogenating them; petroleum resins derived from cyclopentadiene and dicyclopentadiene; and hydrides of these petroleum resins; modified petroleum resins obtained by modifying these petroleum resins with maleic anhydride, maleic acid, fumaric acid, (meth) acrylic acid, phenol, or the like.

As the phenol resin system, a condensate of phenol and formaldehyde can be used. Examples of the phenols include phenol, m-cresol, 3, 5-xylenol, p-alkylphenol, and resorcinol, and examples thereof include resol obtained by addition reaction of these phenols with formaldehyde in the presence of an alkali catalyst, and novolak obtained by condensation reaction of these phenols in the presence of an acid catalyst. Further, a rosin phenol resin obtained by adding phenol to rosin in the presence of an acid catalyst and thermally polymerizing the resin, and the like can be exemplified.

The ketone resin includes known and conventional ketone resins, and formaldehyde resins, cyclohexanone-formaldehyde resins, ketone-aldehyde condensation resins, and the like can be suitably used.

The tackifier may be any one having various softening points, and from the viewpoint of compatibility, hue, thermal stability and the like when mixed with other resins constituting the polyol composition (A), a ketone resin-based tackifier having a softening point of 70 to 160 ℃ and preferably 80 to 100 ℃ or a rosin resin and hydrogenated derivatives thereof having a softening point of 80 to 160 ℃ and preferably 90 to 110 ℃ is preferable, and a ketone resin-based tackifier having a softening point of 70 to 160 ℃ and preferably 80 to 100 ℃ is more preferable. Further, a ketone resin-based tackifier having an acid value of 2 to 20mgKOH/g and a hydroxyl value of 10mgKOH/g or less and a hydrogenated rosin-based tackifier are preferable, and a ketone-based tackifier having an acid value of 2 to 20mgKOH/g and a hydroxyl value of 10mgKOH/g or less is more preferable.

As another preferable mode, the adhesive of the present invention may be used in combination with a known phosphoric acid or a derivative thereof. This further improves the initial adhesiveness of the adhesive, and can solve a problem such as a tunnel effect.

Examples of the phosphoric acids or derivatives thereof to be used herein include phosphoric acids such as hypophosphorous acid, phosphorous acid, orthophosphoric acid and hypophosphorous acid, condensed phosphoric acids such as metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid and superphosphoric acid, and mono-methyl orthophosphate, monoethyl orthophosphate, monopropyl orthophosphate, monobutyl orthophosphate, mono-2-ethylhexyl orthophosphate, monophenyl orthophosphate, monomethyl phosphite, monoethyl phosphite, monopropyl phosphite, monobutyl phosphite, mono-2-ethylhexyl phosphite, monophenyl orthophosphate, di-2-ethylhexyl orthophosphate, dimethyl phosphite, diethyl phosphite, dipropyl phosphite, dibutyl phosphite, di-2-ethylhexyl phosphite and mono-esterified compounds such as diphenyl phosphite, diester compounds and the like, Monoesters and diesters of condensed phosphoric acids and alcohols, for example, products obtained by adding an epoxy compound such as ethylene oxide or propylene oxide to the above phosphoric acids, and epoxy phosphoric esters obtained by adding the above phosphoric acids to aliphatic or aromatic diglycidyl ethers.

One or more of the phosphoric acids or derivatives thereof may be used. The method of inclusion may be simply mixing.

In the adhesive of the present invention, an adhesion promoter may be used. Examples of the adhesion promoter include silane coupling agents, titanate coupling agents, aluminum-based coupling agents, and epoxy resins.

Examples of the silane coupling agent include aminosilanes such as γ -aminopropyltriethoxysilane, γ -aminopropyltrimethoxysilane, N- β (aminoethyl) - γ -aminopropyltrimethyldimethoxysilane, and N-phenyl- γ -aminopropyltrimethoxysilane; epoxy silanes such as beta- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, and gamma-glycidoxypropyltriethoxysilane; vinyl silanes such as vinyltris (β -methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane and γ -methacryloxypropyltrimethoxysilane; hexamethyldisilazane, gamma-mercaptopropyltrimethoxysilane, and the like.

Examples of the titanate-based coupling agent include titanium tetraisopropoxide, titanium tetra-n-butoxide, butyl titanate dimer, tetrastearyl titanate, titanium acetylacetonate, titanium lactate, tetraoctanediol titanate, titanium lactate, and tetrastearoyloxytitanium.

Examples of the aluminum-based coupling agent include aluminum acetylacetonate, and the like.

As the adhesion promoter, a silane coupling agent is preferably used. The content (solid content) of the adhesion promoter is preferably 0.1 part by mass or more, more preferably 0.3 part by mass or more, more preferably 0.5 part by mass or more, and further preferably 0.7 part by mass or more, per 100 parts by mass of the solid content of the polyol composition (a). The content (solid content) of the adhesion promoter is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and still more preferably 5 parts by mass or less, based on 100 parts by mass of the solid content of the polyol composition (a).

In the adhesive of the present invention, the mixing ratio of the polyol composition (a) and the polyisocyanate composition (B) is preferably such that the ratio [ NCO ]/[ OH ] of the total mole number [ OH ] of hydroxyl groups contained in the polyol composition (a) to the mole number [ NCO ] of isocyanate groups contained in the polyisocyanate composition (B) is in the range of 1.5 to 15. Thus, the two-component adhesive is excellent in moldability, heat resistance, and moist heat resistance. [ NCO ]/[ OH ] is more preferably 3 to 10 inclusive, and still more preferably 3 to 8 inclusive.

Further, the ratio [ NCO ']/[ OH ] of the total mole number [ OH ] of hydroxyl groups contained in the polyol composition (a) to the mole number [ NCO' ] of isocyanate groups contained in the isocyanate compound (B2) is preferably 1.5 or less, more preferably 1.3 or less. The lower limit of [ NCO' ]/[ OH ] is not particularly limited, but is preferably 0.3 or more, more preferably 0.5 or more, in order to reliably improve the adhesive strength, moldability, heat resistance, and moist heat resistance.

The reason why the adhesive of the present invention is excellent in moldability, heat resistance and moist heat resistance is not known, but is presumed as follows. When the reactivity of the isocyanate compound is low, the unreacted isocyanate compound may remain in the coating film when considered with respect to the polyisocyanate composition (B). The residual isocyanate compound acts as a plasticizer in a pseudo manner, and causes a decrease in heat resistance of the cured coating film. On the other hand, if the reactivity of the isocyanate compound is too high, the cured coating film becomes too hard and the moldability is lowered. Further, the reaction between the polyol composition (a) and the polyisocyanate composition (B) may occur before the polyol composition (a) is wetted throughout the substrate, and the adhesive strength may be reduced.

The isocyanate compounds (B1) and (B2) have high reactivity at the 1 st isocyanate group, and thus have little risk of remaining in an unreacted state in a large amount in the cured coating film. The reactivity of the 2 nd isocyanate group of each of the isocyanate compounds (B1) and (B2) is very slow as compared with the reactivity of the 1 st isocyanate group, and the isocyanate compound (B1) is significantly slow as compared with (B2). It can be considered that: by using these isocyanate compounds in combination, the reaction proceeds gradually at an appropriate rate in the curing step, and a crosslinked structure is formed which can withstand molding at around room temperature while maintaining the adhesive strength in a high-temperature region.

The present invention is particularly effective for adhesives using a polyol composition (a) having a high surface tension. Various factors have an influence on the surface tension of the compound, and for example, the polyester polyol (a1) having a glass transition temperature as described above and the polyester polyol (a1) having an aromatic ring incorporated in the main skeleton are less likely to be wetted at around room temperature and spread over the substrate. In the present invention, even when the substrates cannot be sufficiently wetted throughout immediately after the polyol composition (a) and the polyisocyanate composition (B) are mixed and applied to adhere the substrates to each other (before the curing step), the adhesive ability is exhibited by heating in the curing step to wet throughout and causing a crosslinking reaction.

The adhesive of the present invention may be in any form of solvent type or solvent-free type. The term "solvent-based" adhesive as used herein means: a method in which an adhesive is applied to a substrate, then the adhesive is heated in an oven or the like to volatilize an organic solvent in the coating film, and then the coating film is bonded to another substrate, and a form used in a so-called dry lamination method. Either or both of the polyol composition (a) and the polyisocyanate composition (B) contain a highly soluble organic solvent capable of dissolving the polyol composition (a) or the polyisocyanate composition (B) used in the present invention. In the case of a solvent-type, an organic solvent used as a reaction medium in the production of the constituent components of the polyol composition (a) or the polyisocyanate composition (B) may be further used as a diluent in the coating. Examples of the highly soluble organic solvent include esters such as ethyl acetate, butyl acetate, and cellosolve acetate, ketones such as acetone, methyl ethyl ketone, isobutyl ketone, and cyclohexanone, ethers such as tetrahydrofuran and dioxane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as dichloromethane and dichloroethane, dimethyl sulfoxide, and dimethyl sulfonamide.

In the present specification, the "solventless" adhesive means: the polyol composition (a) and the polyisocyanate composition (B) are in the form of an adhesive used in a method of applying the adhesive to a substrate substantially without containing the above-mentioned highly soluble organic solvent, particularly ethyl acetate or methyl ethyl ketone, and then adhering the adhesive to another substrate without going through a step of volatilizing the solvent by heating in an oven or the like, so-called a solventless lamination method. When the organic solvent used as a reaction medium in the production of the constituent components of the polyol composition (a) or the polyisocyanate composition (B) or the raw materials thereof is not removed and a slight amount of the organic solvent remains in the polyol composition (a) or the polyisocyanate composition (B), it is regarded as substantially not containing the organic solvent. In addition, in the case where the polyol composition (a) contains a low molecular weight alcohol, the low molecular weight alcohol reacts with the polyisocyanate composition (B) to become a part of the coating film, and therefore it is not necessary to volatilize it after coating. Therefore, this form is also considered as a solventless adhesive.

In the case where the adhesive of the present invention is a solvent-based adhesive, the viscosity can be reduced by dilution with a solvent, and therefore, the polyol composition (a) or the polyisocyanate composition (B) can be used even if the viscosity is slightly high. On the other hand, in the case of the solvent-free type, low viscosity is regarded as important in the property of lowering viscosity by heating, and as a means for lowering viscosity, a means for lowering the concentration of an aromatic compound contributing to viscosity is generally used for the polyisocyanate composition (B).

The adhesive of the present invention may contain various additives such as an ultraviolet absorber, an antioxidant, a silicon-based additive, a fluorine-based additive, a rheology control agent, a defoaming agent, an antistatic agent, and an antifogging agent.

The application of the adhesive of the present invention is not particularly limited, and the adhesive is excellent in adhesive strength, processability, moist heat resistance and heat resistance, and thus can be suitably used for a battery packaging material.

< layered product >

The laminate of the present invention is obtained by bonding a plurality of substrates by a dry lamination method or a solventless lamination method using the adhesive of the present invention. Examples of the substrate include paper, synthetic resin films obtained from olefin-based resins, acrylonitrile-butadiene-styrene copolymers (ABS resins), polyvinyl chloride-based resins, fluorine-based resins, poly (meth) acrylic resins, carbonate-based resins, polyamide-based resins, polyimide-based resins, polyphenylene ether-based resins, polyphenylene sulfide-based resins, and polyester-based resins, and metal foils such as copper foils and aluminum foils.

The film thickness of the substrate is not particularly limited, and may be selected from, for example, 10 to 400 μm. In order to improve the adhesion between the base material and the adhesive, the surface of the base material to which the adhesive is applied may be subjected to surface treatment. Examples of the surface treatment include corona treatment, plasma treatment, ozone treatment, flame treatment, and radiation treatment.

< packaging Material for Battery >

As shown in fig. 1, the battery packaging material includes a laminate in which at least an outer layer-side base material layer 1, an adhesive layer 2, a metal layer 3, and a sealant layer 4 are laminated in this order. In the battery packaging material of the present invention, the outer-layer side substrate layer 1 is an outermost layer, and the sealant layer 4 is an innermost layer. That is, when the battery is assembled, the battery elements are sealed by thermally welding the sealant layers 4 positioned around the battery elements to each other, thereby sealing the battery elements. The adhesive of the present invention is used for the adhesive layer 2. As shown in fig. 2, the battery packaging material of the present invention may be provided with an adhesive layer 5 between the metal layer 3 and the sealant layer 4 as needed for the purpose of improving the adhesiveness therebetween.

(outer side substrate layer 1)

In the packaging material for a battery of the present invention, the outer-layer side substrate layer 1 is a layer forming the outermost layer. The material for forming the outer layer side substrate layer 1 is not particularly limited as long as it has insulation properties, and examples thereof include resin films such as polyester resins, polyamide resins, epoxy resins, acrylic resins, fluorine resins, polyurethane resins, silicone resins, phenol resins, and mixtures and copolymers thereof. Among these, polyester resins and polyamide resins are preferable, and biaxially stretched polyester resins and biaxially stretched polyamide resins are more preferable. Specific examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolyester, and polycarbonate. Specific examples of the polyamide resin include nylon 6, a copolymer of nylon 6 and nylon 6, nylon 6, 10, and m-xylylene adipamide (MXD 6).

The outer-layer side substrate layer 1 may be formed of 1 resin film, but may be formed of 2 or more resin films, for example, a multilayer film including a polyethylene terephthalate film and a polyamide film, in order to improve pinhole resistance and insulation properties. When the outer-layer side substrate layer 1 is formed of a plurality of resin films, the resin films may be laminated with each other only by an adhesive component such as an adhesive or an adhesive resin, and the kind, amount, and the like of the adhesive component used are the same as those of the adhesive layer 2 or the adhesive layer 5 described later. The method for laminating 2 or more resin films is not particularly limited, and a known method can be used, and examples thereof include a dry lamination method, a sandwich lamination method, and the like, and preferably a dry lamination method. When the lamination is performed by a dry lamination method, an adhesive is preferably used as the adhesive layer. In this case, the thickness of the adhesive layer is, for example, about 0.5 to 10 μm.

The thickness of the outer-layer side substrate layer 1 is not particularly limited as long as the battery packaging material satisfies the above physical properties, and is, for example, about 10 to 50 μm, preferably about 15 to 35 μm. When a polyester film is used, the thickness is preferably 9 to 50 μm, and when a polyamide film is used, the thickness is preferably 10 to 50 μm. The packaging material can ensure sufficient strength, reduce stress during stretch forming and draw forming, and improve formability.

(Metal layer 3)

In the battery packaging material, the metal layer 3 functions as a barrier layer for preventing water vapor, oxygen, light, and the like from entering the battery, in addition to improving the strength of the battery packaging material. Specific examples of the metal constituting the metal layer 3 include aluminum, stainless steel, and titanium, and aluminum is preferable. The metal layer 3 may be formed of metal foil, metal vapor deposition, or the like, preferably metal foil, and more preferably aluminum foil. In addition, at least one surface, preferably both surfaces, of the metal layer 3 are preferably subjected to chemical conversion treatment for stabilization of adhesion, prevention of dissolution, corrosion, or the like. Here, the chemical conversion treatment is a treatment for forming an acid-resistant coating film on the surface of the metal layer.

The thickness of the metal layer 3 is not particularly limited as long as the battery packaging material satisfies the above physical properties, and may be, for example, about 10 to 50 μm, and preferably about 25 to 45 μm.

(sealant layer 4)

In the battery packaging material of the present invention, the sealant layer 4 is an innermost layer and is a layer that seals the battery element by thermally fusing the sealant layers to each other when the battery is assembled.

The resin component used for the sealant layer 4 is not particularly limited as long as it can be heat-welded, and examples thereof include polyolefins, cyclic polyolefins, carboxylic acid-modified polyolefins, and carboxylic acid-modified cyclic polyolefins.

Specific examples of the polyolefin include polyethylenes such as low density polyethylene, medium density polyethylene, high density polyethylene, and linear low density polyethylene; polypropylene such as homopolypropylene, a block copolymer of polypropylene (for example, a block copolymer of propylene and ethylene), a random copolymer of polypropylene (for example, a random copolymer of propylene and ethylene), and the like; ethylene-butene-propylene terpolymers, and the like. Among these polyolefins, polyethylene and polypropylene are preferably listed.

The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin as a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, isoprene, and the like. Examples of the cyclic monomer as a constituent monomer of the cyclic polyolefin include cyclic olefins such as norbornene; specific examples thereof include cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene and norbornadiene. Among these polyolefins, cyclic olefins are preferably used, and norbornene is more preferably used.

The above carboxylic acid-modified polyolefin means: a polymer modified by block polymerization or graft polymerization of the above polyolefin with a carboxylic acid. Examples of the carboxylic acid used for modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

The above carboxylic acid-modified cyclic polyolefin means: a polymer obtained by substituting a part of monomers constituting the cyclic polyolefin with an α, β -unsaturated carboxylic acid or an anhydride thereof and copolymerizing the same, or by block polymerization or graft polymerization of an α, β -unsaturated carboxylic acid or an anhydride thereof with respect to the cyclic polyolefin. The cyclic polyolefin modified with a carboxylic acid is the same as described above. The carboxylic acid used for the modification is the same as the carboxylic acid used for the modification of the acid-modified cycloolefin copolymer.

The sealant layer 4 may be formed of 1 resin component alone, or may be formed of a polymer blend in which 2 or more resin components are combined. Further, the sealant layer 4 may be formed of only 1 layer, or may be formed of 2 or more layers using the same or different resin components.

The thickness of the sealant layer 4 is not particularly limited as long as the battery packaging material satisfies the above physical properties, and is, for example, about 10 to 100 μm, preferably about 20 to 90 μm.

(adhesive layer 5)

In the battery packaging material of the present invention, the adhesive layer 5 is a layer provided between the metal layer 3 and the sealant layer 4 as needed to firmly adhere them.

The adhesive layer 5 is formed of an adhesive capable of bonding the metal layer 3 and the sealant layer 4. Examples of the adhesive layer used for the adhesive layer 5 include adhesives obtained by combining a polyolefin resin and a polyfunctional isocyanate, adhesives obtained by combining a polyol and a polyfunctional isocyanate, and adhesives containing a modified polyolefin resin, a heterocyclic compound, and a curing agent. Alternatively, the metal layer 3 and the sealant layer 4 may be adhered to each other by melt-extruding an adhesive such as acid-modified polypropylene onto the metal layer by a T-die extruder to form the adhesive layer 5 and then overlapping the sealant layer 4 on the adhesive layer 5.

When both the adhesive layer 2 and the adhesive layer 5 need to be cured, they may be cured at the same time. The curing temperature is set to room temperature to 90 ℃ to complete curing for 2 days to 2 weeks, thereby exhibiting moldability.

The thickness of the adhesive layer 5 is not particularly limited as long as the battery packaging material satisfies the above physical properties, and is, for example, about 0.5 to 50 μm, preferably about 2 to 30 μm.

(coating layer 6)

In the battery packaging material of the present invention, the coating layer 6 may be provided on the outer layer side base material layer 1 (the side of the outer layer side base material layer 1 opposite to the metal layer 3) as necessary for the purpose of improving design properties, electrolyte resistance, scratch resistance, moldability, and the like. The coating layer 6 is a layer located at the outermost layer when the battery is assembled.

The coating layer 6 can be formed using, for example, polyvinylidene chloride, polyester resin, urethane resin, acrylic resin, epoxy resin, or the like, and is preferably formed using a two-component curable resin. Examples of the two-component curable resin for forming the coating layer 6 include a two-component curable urethane resin, a two-component curable polyester resin, and a two-component curable epoxy resin. Further, a matting agent may be added to the coating layer 6.

Examples of the matting agent include fine particles having a particle diameter of about 0.5nm to 5 μm. The material of the matting agent is not particularly limited, and examples thereof include metals, metal oxides, inorganic substances, and organic substances. The shape of the matting agent is not particularly limited, and examples thereof include a spherical shape, a fibrous shape, a plate shape, an irregular shape, and a hollow spherical shape. Specific examples of the matting agent include talc, silica, graphite, kaolin, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, carbon black, carbon nanotubes, high-melting nylon, crosslinked acrylic acids, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, and nickel. These matting agents may be used alone, or 2 or more kinds may be used in combination. Among these matting agents, silica, barium sulfate, and titanium oxide are preferable from the viewpoints of dispersion stability, cost, and the like. The matting agent may be subjected to various surface treatments such as an insulating treatment and a high-dispersibility treatment.

The method for forming the coating layer 6 is not particularly limited, and examples thereof include a method in which a two-component curable resin for forming the coating layer 6 is applied to one surface of the outer layer side base material layer 1. When the matting agent is blended, the two-component curable resin may be mixed with the matting agent and then coated.

(method for producing Battery packaging Material)

The method for producing the battery packaging material of the present invention is not particularly limited as long as a laminate in which layers having a specific composition are laminated can be obtained, and the following methods can be exemplified.

First, a laminate (hereinafter, also referred to as "laminate a") in which the outer-layer side substrate layer 1, the adhesive layer 2, and the metal layer 3 are laminated in this order is formed. Specifically, the laminate a may be formed by the following dry lamination method: the adhesive of the present invention is applied to the outer layer side base material layer 1 or the metal layer 3 whose surface has been subjected to chemical conversion treatment as necessary by a coating method such as extrusion, gravure coating, roll coating, or the like, and dried, and then the metal layer 3 or the outer layer side base material layer 1 is laminated and the adhesive layer 2 is cured.

Next, a sealant layer 4 was laminated on the metal layer 3 of the laminate a. When the sealant layer 4 is directly laminated on the metal layer 3, the resin component constituting the sealant layer 4 may be applied to the metal layer 3 of the laminate a by a method such as a gravure coating method or a roll coating method. When the adhesive layer 5 is provided between the metal layer 3 and the sealant layer 4, for example, the following methods can be mentioned: a method of laminating by co-extruding the adhesive layer 5 and the sealant layer 4 on the metal layer 3 of the laminate a (co-extrusion lamination method); a method of separately forming a laminate in which the adhesive layer 5 and the sealant layer 4 are laminated, and laminating the laminate on the metal layer 3 of the laminate a by a hot lamination method; a method of laminating an adhesive for forming the adhesive layer 5 on the metal layer 3 of the laminate a by an extrusion method or a method of applying a solution, drying at a high temperature, and sintering, and laminating a sealant layer 4 formed in a sheet shape in advance on the adhesive layer 5 by a hot lamination method; a method (sandwich lamination method) in which the laminate a and the sealant layer 4 are bonded to each other via the adhesive layer 5 while the molten adhesive layer 5 is poured between the metal layer 3 of the laminate a and the sealant layer 4 formed into a sheet in advance.

When the coating layer 6 is provided, the coating layer 6 is laminated on the surface of the outer base material layer 1 opposite to the metal layer 3. The coating layer 6 is formed by, for example, applying the above-described resin forming the coating layer 6 to the surface of the outer-layer side base material layer 1. The order of the step of laminating the metal layer 3 on the surface of the outer layer-side base material layer 1 and the step of laminating the coating layer 6 on the surface of the outer layer-side base material layer 1 is not particularly limited. For example, after the coating layer 6 is formed on the surface of the outer-layer-side base material layer 1, the metal layer 3 may be formed on the surface of the outer-layer-side base material layer 1 opposite to the coating layer 6.

In this way, a laminate comprising the coating layer 6/outer-layer side base material layer 1/adhesive layer 2/metal layer 3 whose surface has been subjected to chemical conversion treatment as needed/adhesive layer 5/sealant layer 4 as needed is formed, but the laminate may be further subjected to heat treatment such as heat roller contact type, hot air type, near infrared type or far infrared type to enhance the adhesion between the adhesive layer 2 and the adhesive layer 5 provided as needed. The conditions for such heat treatment include, for example, heat treatment at 150 to 250 ℃ for 1 to 5 minutes.

In the battery packaging material of the present invention, each layer constituting the laminate may be subjected to surface activation treatment such as corona treatment, plasma treatment, oxidation treatment, and ozone treatment as necessary for improving or stabilizing film formability, lamination processing, secondary processing (bagging, embossing) suitability of the final product, and the like.

< Container for Battery >

The battery container of the present invention can be obtained by molding the above-described battery packaging material such that the outer layer side base material layer 1 forms a convex surface and the sealant layer 4 forms a concave surface.

As a method of molding the concave portion, the following method is available.

Heated compressed air forming: a method of forming the concave portion by sandwiching the battery packaging material between a female mold having a hole for supplying high-temperature and high-pressure air and a male mold having a pocket-shaped concave portion and supplying air while heating and softening the battery packaging material.

Flat compressed air forming method of preheater: a method of heating and softening the battery packaging material, and then sandwiching the battery packaging material between a female mold having a hole for supplying high-pressure air and a male mold having a pocket-shaped concave portion, and supplying air to form the concave portion.

Roll-to-roll vacuum forming: the method comprises heating and softening the packaging material for battery partially with a heating roller, and vacuumizing the recessed part of the roller having pocket-shaped recessed part to form the recessed part.

Pin forming method: and a method of heating and softening the substrate sheet and then pressing the substrate sheet with a pocket-like concave-convex mold.

A pre-heater-assisted die plug compressed air forming method: a method of heating and softening the battery packaging material, sandwiching the battery packaging material between a female mold having a hole for supplying high-pressure air and a male mold having a pocket-shaped concave portion, and supplying air to form the concave portion, and a method of raising and lowering a convex plunger at the time of molding to assist molding.

Among them, the pre-heater assisted plug-and-press air molding method is preferable as the heating vacuum molding method from the viewpoint of obtaining a uniform thickness of the substrate after molding.

(use of a packaging Material for batteries)

The battery packaging material of the present invention can be used as a battery container for hermetically containing battery elements such as a positive electrode, a negative electrode, and an electrolyte.

Specifically, the battery packaging material according to the present invention is a battery using the battery packaging material, in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is covered so that a flange portion (a region where sealant layers are in contact with each other) can be formed around the battery element in a state where a metal terminal to which each of the positive electrode and the negative electrode is connected protrudes outward, and the sealant layers of the flange portions are heat-sealed and sealed with each other. When the battery element is contained in the battery packaging material of the present invention, the battery packaging material of the present invention is used so that the sealant portion thereof is on the inside (the surface in contact with the battery element).

The battery packaging material of the present invention can be used for both primary batteries and secondary batteries, and can be preferably used for secondary batteries. The type of secondary battery to which the battery packaging material of the present invention is applied is not particularly limited, and examples thereof include a lithium ion battery, a lithium ion polymer battery, a lead storage battery, a nickel/hydrogen storage battery, a nickel/cadmium storage battery, a nickel/iron storage battery, a nickel/zinc storage battery, a silver oxide/zinc storage battery, a metal air battery, a polyvalent cation battery, a capacitor (condenser), and a capacitor (capacitor). Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are suitable as an application target of the battery packaging material of the present invention.

Examples

The present invention will be described in more detail below with reference to specific synthetic examples and examples, but the present invention is not limited to these examples. In the following examples, "part" and "%" represent "part by mass" and "% by mass", respectively, unless otherwise specified.

< preparation of polyester polyol >

Synthesis example 1 Synthesis of polyester polyol (A1)

Polyester polyol was synthesized by a predetermined method using 790.8 parts of isophthalic acid, 339.4 parts of terephthalic acid, 20.0 parts of trimellitic anhydride, 738.0 parts of 1, 6-hexanediol, and 107.4 parts of neopentyl glycol. The obtained polyester polyol was diluted with ethyl acetate until the resin solid content became 58%, to obtain a polyester polyol (A1) having a number average molecular weight (Mn) of 7900, a weight average molecular weight (Mw) of 25700, a resin hydroxyl value (in terms of solid content) of 22.2mgKOH/g, a resin acid value (in terms of solid content) of 0.82mgKOH/g, and a glass transition temperature (Tg) of 7.3 ℃.

Synthesis example 2 Synthesis of polyester polyol (A2)

Polyester polyol was synthesized by a predetermined method using 790.8 parts of isophthalic acid, 339.4 parts of terephthalic acid, 20.0 parts of trimellitic anhydride, 738.0 parts of 1, 6-hexanediol, and 107.4 parts of neopentyl glycol. The obtained polyester polyol was diluted with ethyl acetate to a resin solid content of 58% to obtain a polyester polyol (A2') having a number average molecular weight (Mn) of 7000, a weight average molecular weight (Mw) of 23500, a resin hydroxyl value (in terms of solid content) of 22.4mgKOH/g, a resin acid value (in terms of solid content) of 1.26mgKOH/g, and a glass transition temperature (Tg) of 2.1 ℃.

The chain extension reaction was carried out using 900 parts of polyester polyol (a 2') and 13.47 parts of hexamethylene diisocyanate. When the weight% of isocyanate reached 0.25% or less, the reaction was stopped, and the reaction mixture was diluted with ethyl acetate until the resin solid content became 40%, whereby a polyester polyol (A2) having a number average molecular weight (Mn) of 13700, a weight average molecular weight (Mw) of 128600, a resin hydroxyl value of 7.6mgKOH/g, a resin acid value of 1.35mgKOH/g, and a glass transition temperature point (Tg) of 9.9 ℃ was obtained.

Synthesis example 3 Synthesis of polyester polyol (A3)

Polyester polyol was obtained by a predetermined method using 697.2 parts of terephthalic acid, 72.9 parts of ethylene glycol and 229.9 parts of 1, 2-propanediol. The obtained polyester polyol was diluted with methyl ethyl ketone until the solid content of the resin became 30%, to obtain a polyester polyol (A3) having a number average molecular weight (Mn) of 8400, a weight average molecular weight (Mw) of 61300, a resin hydroxyl value (in terms of solid content) of 5.0mgKOH/g, a resin acid value (in terms of solid content) of 4.0mgKOH/g, and a glass transition temperature of 84 ℃.

The physical properties of the polyester polyol were measured in the following manner.

(molecular weight measurement method)

A measuring device: HLC-8320GPC, manufactured by Tosoh corporation

A detector: RI (differential refractometer)

The measurement conditions were as follows: column temperature 40 deg.C

Solvent tetrahydrofuran

Flow rate 0.35 ml/min

The standard is as follows: monodisperse polystyrene

(acid value measurement method)

A sample (5.0 g) was precisely weighed, dissolved in 30mL of a neutral solvent, and titrated with a 0.1mol/L potassium hydroxide solution (methanolic). Phenolphthalein was used as the indicator. The measurement result was converted into the amount of potassium hydroxide required for neutralizing 1g of the sample, and the unit was mgKOH/g.

(measurement of hydroxyl value)

A sample (4.0 g, in terms of solid content) was precisely weighed, 25mL of an acetylating agent comprising acetic anhydride/pyridine (in a volume ratio of 1/19) was added, and the mixture was sealed and heated at 100 ℃ for 1 hour. After acetylation, 10mL of ion-exchanged water and 100mL of tetrahydrofuran were added, and titration was performed using a 0.5mol/L potassium hydroxide solution (alcoholic). Phenolphthalein was used as the indicator. The measurement result was converted into the amount of potassium hydroxide required for neutralizing acetic acid generated when 1g of the sample was acetylated, and the unit was mgKOH/g.

(glass transition temperature measurement method)

Using DSC, 5mg of the sample was heated from room temperature to 200 ℃ at 10 ℃/min under a 30 mL/min nitrogen gas stream, then cooled to-80 ℃ at 10 ℃/min, and then heated to 150 ℃ at 10 ℃/min again to measure the DSC curve. In the measurement results observed in the second temperature-raising step, the intersection of the straight line extending from the base line on the low temperature side to the high temperature side and the tangent drawn at the point at which the slope of the curve in the step-like portion of glass transition becomes maximum is regarded as the glass transition point, and the temperature at that time is regarded as the glass transition temperature.

< preparation of adhesive >

(example 1)

KBM-403 (nonvolatile silane coupling agent, 100% from shin-Etsu chemical Co., Ltd.) was added to the polyester polyol (A1), and the mixture was sufficiently stirred until the KBM-403 was completely dissolved. To these mixtures were added isocyanate (B1-1) and isocyanate (B2-1), and ethyl acetate was added so that the nonvolatile matter became 25%, followed by stirring to prepare an adhesive of example 1. Table 1 shows the amounts of the respective components (solid contents) in the adhesive of example 1.

(example 2) to (example 6)

Adhesives of examples 2 to 6 were produced in the same manner as in example 1, except that the materials and compounding ratios used for preparing the adhesives were adjusted to the values shown in table 1.

Comparative examples 1 to 5

Adhesives of comparative examples 1 to 5 were produced in the same manner as in example 1, except that the materials and compounding ratios used for preparing the adhesives were adjusted to the values shown in table 2.

Other compounds in tables 1 and 2 are shown below.

TEGO Variplus AP: ketone-aldehyde condensation resin manufactured by EVONIC Inc

Isocyanate (B1-1): trimethylolpropane adduct of toluene diisocyanate (NCO% ═ 17.7)

Isocyanate (B2-1): 4, 4' -MDI (NCO% ═ 33.3)

Isocyanate (B2-2): carbodiimide-modified MDI monomer (NCO% ═ 29.5%)

Isocyanate (B2-3): 50/50 (wt%) mixture of 4, 4 '-MDI and 2, 4' -MDI (NCO% ═ 33.3%)

Isocyanate (B3-1): addition type polyisocyanate of hexamethylene diisocyanate (NCO% ═ 9.5%)

Isocyanate (B3-2): uretdione type polyisocyanate of hexamethylene diisocyanate (NCO% ═ 21.8%)

< production of Battery packaging Material FIG. 2 construction >

(example 1)

The adhesive of example 1 as the adhesive layer 2 was applied to the matte surface of a 40 μm thick aluminum foil as the metal layer 3 in an amount of 4 g/m using a dry laminator to evaporate the solvent, and then a 25 μm thick stretched polyamide film was laminated as the outer layer side substrate layer 1.

Next, an adhesive for the adhesive layer 5 was applied to the glossy surface of the aluminum foil of the metal layer 3 of the obtained laminated film by a dry laminator in an amount of 4 g/m, the solvent was evaporated, and then an unstretched polypropylene film having a thickness of 40 μm was laminated as the sealant layer 4, followed by curing (aging) at 60 ℃ for 5 days to cure the adhesive, thereby obtaining a laminate.

(example 2) to (example 6)

The same procedure as in example 1 was repeated except that the adhesive of examples 2 to 6 was used as the adhesive layer 2 to obtain the battery packaging materials of examples 2 to 6.

Comparative examples 1 to 5

The same procedure as in example 1 was repeated except that the adhesive of comparative examples 1 to 5 was used as the adhesive layer 2 to obtain battery packaging materials of comparative examples 1 to 5.

Evaluation of the battery packaging material was performed as follows.

< adhesion Strength >

The adhesive strength at the interface between the outer layer side substrate layer 1 and the metal layer 3 of the packaging material for batteries of examples and comparative examples was evaluated using an Autograph AGS-J manufactured by Shimadzu corporation under conditions of a peeling speed of 100 mm/min, a peeling width of 15mm, and a peeling mode of 180 DEG peeling. Higher values indicate more suitable adhesives.

< moldability >

The battery packaging materials of examples and comparative examples were cut into a size of 60X 60mm using a "1-ton bench servo press (SBN-1000)" manufactured by Shangang, Co., Ltd, as blanks (materials to be molded, raw materials). The blank was subjected to stretch forming by changing the forming height from 4.5mm to 6.5mm using a straight die having a free forming height so that the matte surface of the aluminum foil became convex, and formability was evaluated by the maximum forming height without causing lifting between the layers due to breakage of the aluminum foil.

The punch shape of the die used was: a square with a single side of 30mm, an edge angle R2mm and a punch shoulder R1mm, wherein the shape of a die hole of the used die is as follows: a single side 34mm square, a die hole wall angle R2mm, a die hole shoulder R: 1mm, and the clearance between the punch and the die hole is 0.3mm on one side. The gap causes a tilt corresponding to the molding height. The following 3-level evaluations were made according to the height of the molding.

O: : 5.0mm or more (practically excellent)

Δ: 4.5mm (practical range)

X: fracture of aluminum foil at 4.5mm, and floating between layers

< Heat resistance >

The battery packaging material of the examples or comparative examples was cut into a size of 60 × 60mm using a "1-ton bench servo press (SBN-1000)" manufactured by shanggang, ltd, and was subjected to stretch molding at a molding height of 5.0mm using a straight mold having a free molding height such that the aluminum foil matte surface was located on the outside. The side wall portion was brought into contact with the flange portion of the obtained 30mm square tray at 190 ℃ for 3 seconds, and the appearance of the vicinity of the boundary portion between the flange portion and the side wall portion was confirmed to evaluate whether or not the floating occurred between the stretched polyamide film and the aluminum foil.

O: no float (excellent in practice)

Δ: occurrence of floating (practical range)

X: float up occurs

< moist Heat resistance >

The battery packaging material of the examples or comparative examples was cut into a size of 60 × 60mm using a "1-ton bench servo press (SBN-1000)" manufactured by shanggang, ltd, and was subjected to stretch molding at a molding height of 5.0mm using a straight mold having a free molding height such that the aluminum foil matte surface was located on the outside. The square tray of 30mm was placed in a constant temperature and humidity bath at 85 ℃ and 85% RH, and allowed to stand for 48 hours. The tray was taken out from the constant temperature and humidity chamber, and the appearance of the tray in the vicinity of the boundary between the flange portion and the side wall portion was confirmed to evaluate whether or not the floating occurred between the stretched polyamide film and the aluminum foil.

O: no float (excellent in practice)

Δ: occurrence of floating (practical range)

X: float up occurs

The results are shown in tables 1 and 2. In the NCO/OH ratios in tables 2 and 3, the contents in the column "entire" are the values of [ NCO ]/[ OH ] described above, and the contents in the column "B2" are the values of [ NCO' ]/[ OH ]. The parenthesized values in the column "B2" are equivalent ratios of isocyanate groups to hydroxyl groups derived from the isocyanate compound (B3) used in place of the isocyanate compound (B2).

[ Table 1]

[ Table 2]

From the results, it is found that: by using the adhesive of the present invention, a battery packaging material having excellent moldability, in which the interlayer adhesion strength is not reduced after the heat fusion of the sealant layers for sealing the battery element and further after the long-term durability test under high temperature and high humidity, and in which the appearance defects such as interlayer floating are suppressed can be obtained.

Claims

1. A two-component adhesive characterized by comprising a polyol composition A and a polyisocyanate composition B,

the polyisocyanate composition B comprises an isocyanate compound B1 and an isocyanate compound B2,

the isocyanate compound B1 contains an aromatic polyisocyanate, and the isocyanate compound B2 contains at least one selected from the group consisting of 2, 2 '-diphenylmethane diisocyanate, 2, 4' -diphenylmethane diisocyanate, 4 '-diphenylmethane diisocyanate, and carbodiimide-modified diphenylmethane diisocyanate obtained by condensing at least one of 2, 2' -diphenylmethane diisocyanate, 2, 4 '-diphenylmethane diisocyanate, and 4, 4' -diphenylmethane diisocyanate in the presence of a catalyst.

2. The two-pack adhesive according to claim 1, wherein the ratio [ NCO ]/[ OH ] of the number of moles of isocyanate groups [ NCO ] contained in the polyisocyanate composition B to the total number of moles of hydroxyl groups [ OH ] contained in the polyol composition A is 1.5 to 15.

3. The two-pack adhesive according to claim 1 or 2, wherein the ratio [ NCO ']/[ OH ] of the number of moles of isocyanate groups [ NCO' ] in the isocyanate compound B2 to the total number of moles of hydroxyl groups [ OH ] in the polyol composition A is 0.3 to 1.5.

4. The two-component adhesive according to any one of claims 1 to 3, wherein the isocyanate compound B1 is toluene diisocyanate or a derivative of toluene diisocyanate.

5. The two-component adhesive according to any one of claims 1 to 4, wherein the isocyanate compound B1 is an adduct of toluene diisocyanate.

6. The two-pack adhesive according to any one of claims 1 to 5, wherein the polyol composition A comprises a polyester polyol A1 essentially composed of a polybasic acid or a derivative thereof and a polyhydric alcohol, and the ratio of the polybasic acid having an aromatic ring or the derivative thereof in the polybasic acid or the derivative thereof is 30 mol% or more.

7. The two-pack adhesive according to any one of claims 1 to 6, wherein the polyol composition A comprises a polyester polyol A1 containing a polybasic acid or a derivative thereof and a polyhydric alcohol as essential raw materials, and the number average molecular weight of the polyester polyol A1 is 2000 to 100000.

8. A laminate obtained by bonding a plurality of substrates with the two-component adhesive according to any one of claims 1 to 7.

9. A battery packaging material comprising at least an outer layer-side base material layer 1, an adhesive layer 2, a metal layer 3 and a sealant layer 4 laminated in this order, wherein the adhesive layer 2 is a cured product of the two-component adhesive according to any one of claims 1 to 7.

10. A battery container obtained by molding the battery packaging material according to claim 9.

11. A battery using the battery container according to claim 10.